1、 2015 CUFEC H A P T E R2What are economists two roles? How do they differ? What are models? How do economists use them?What are the elements of the Circular-Flow Diagram 循環(huán)流量圖? What concepts does the diagram illustrate? How is the Production Possibilities Frontier （生產(chǎn)可能性邊界） related to opportunity co

2、st? What other concepts does it illustrate?What is the difference between microeconomics and macroeconomics? Between positive and normative （實(shí)證分析與規(guī)范分析）?1THINKING LIKE AN ECONOMIST2The Economist as Scientist作為科學(xué)家的經(jīng)濟(jì)學(xué)家作為科學(xué)家的經(jīng)濟(jì)學(xué)家Economists play two roles:1. Scientists（科學(xué)家）: try to explain the world（解釋世

3、界，Why）2. Policy advisors（政策咨詢者）: try to improve it（改造世界，How）In the first, economists employ the scientific method（科學(xué)方（科學(xué)方法）法）, the dispassionate （不帶偏見的） development and testing of theories about how the world works. （利用科學(xué)方法解釋世界如何運(yùn)行）科學(xué)方法：觀察提出理論進(jìn)一步觀察（檢測(cè)理論）與自然科學(xué)不同的是，經(jīng)濟(jì)學(xué)往往無法做實(shí)驗(yàn)關(guān)注歷史發(fā)生的自然實(shí)驗(yàn)THINKING LIKE A

4、N ECONOMIST3Assumptions & Models假設(shè)假設(shè)&模型模型Assumptions simplify the complex world, make it easier to understand.（假設(shè)只是為了便于理解：現(xiàn)實(shí)太復(fù)雜）Example: To study international trade, assume two countries and two goods. Unrealistic, but simple to learn and gives useful insights about the real world.Model: a

5、highly simplified representation of a more complicated reality. （對(duì)復(fù)雜的現(xiàn)實(shí)世界近似描述）Economists use models to study economic issues. （經(jīng)濟(jì)學(xué)家利用經(jīng)濟(jì)學(xué)模型來研究問題） THINKING LIKE AN ECONOMIST4Some Familiar ModelsA road map模型類似于地圖模型需要在貼近現(xiàn)實(shí)和盡量簡化之間進(jìn)行權(quán)衡。THINKING LIKE AN ECONOMIST5Some Familiar ModelsA model of human anatom

6、y （人體解剖學(xué)） from high school biology classTHINKING LIKE AN ECONOMIST6Some Familiar ModelsA model airplaneTHINKING LIKE AN ECONOMIST7Some Familiar ModelsThe model teeth at the dentists officeDont forget to floss!THINKING LIKE AN ECONOMIST8Our First Model: The Circular-Flow DiagramThe Circular-Flow Diag

7、ram（經(jīng)濟(jì)循環(huán)圖）（經(jīng)濟(jì)循環(huán)圖）: a visual model of the economy, shows how dollars flow through markets among households and firms 經(jīng)濟(jì)循環(huán)圖一個(gè)說明貨幣貨幣如何通過市場(chǎng)市場(chǎng)在家庭家庭和企業(yè)企業(yè)之間流動(dòng)流動(dòng)的直觀經(jīng)濟(jì)學(xué)模型。Two types of “actors”: households（家庭） & firms Two markets:the market for goods and services （商品與勞務(wù)市場(chǎng)）the market for “factors of produc

8、tion” （生產(chǎn)要素市場(chǎng)）THINKING LIKE AN ECONOMIST9Factors of ProductionFactors of production（生產(chǎn)要素）（生產(chǎn)要素）: the resources the economy uses to produce goods & services, includinglabor land capital (buildings & machines used in production)THINKING LIKE AN ECONOMIST10FIGURE 1: The Circular-Flow DiagramHou

9、seholds （家庭）（家庭）: Own the factors of production, sell/rent them to firms for income Buy and consume goods & servicesHouseholds FirmsFirms （企業(yè)）（企業(yè)）: Buy/hire factors of production, use them to produce goods and services Sell goods & servicesTHINKING LIKE AN ECONOMIST11FIGURE 1: The Circular-F

10、low DiagramMarkets for Factors of ProductionHouseholdsFirms IncomeWages, rent, profitFactors of productionLabor, land, capital SpendingG & S boughtG & S soldRevenueMarkets for Goods（G） & Services（S）THINKING LIKE AN ECONOMIST12經(jīng)濟(jì)循環(huán)圖經(jīng)濟(jì)循環(huán)圖企業(yè)企業(yè)家庭家庭生產(chǎn)要素生產(chǎn)要素市場(chǎng)市場(chǎng)物品與勞務(wù)物品與勞務(wù)市場(chǎng)市場(chǎng)支出支出收入收入工資、租金工資、租金

11、和利潤和利潤收入收入銷售商品銷售商品和服務(wù)和服務(wù)購買商品購買商品和服務(wù)和服務(wù)勞動(dòng)、土地勞動(dòng)、土地和資本和資本生產(chǎn)投入生產(chǎn)投入THINKING LIKE AN ECONOMIST13Our Second Model: 生產(chǎn)可能性邊界生產(chǎn)可能性邊界The Production Possibilities FrontierThe Production Possibilities Frontier （ PPF ）: a graph that shows the combinations of two goods the economy can possibly produce given the av

12、ailable resources and the available technology。PPF 表示在可得到的生產(chǎn)要素與生產(chǎn)技術(shù)既定時(shí)，一個(gè)經(jīng)濟(jì)所表示在可得到的生產(chǎn)要素與生產(chǎn)技術(shù)既定時(shí)，一個(gè)經(jīng)濟(jì)所能生產(chǎn)的產(chǎn)品數(shù)量的各種組合的圖形。能生產(chǎn)的產(chǎn)品數(shù)量的各種組合的圖形。Example: Two goods: computers and wheatOne resource: labor (measured in hours)Economy has 50,000 labor hours per month available for production.PPF ExampleProducing

13、one computer requires 100 hours labor.Producing one ton of wheat requires 10 hours labor.5,00004,0001002,5002501,00040050,000040,00010,00025,00025,00010,00040,0000500050,000EDCBAWheatComputersWheatComputersProductionEmployment of labor hoursTHINKING LIKE AN ECONOMIST15Point on graphProductionCom-put

14、ersWheatA5000B4001,000C2502,500D1004,000E05,000ABCDEPPF ExampleA.On the graph, find the point that represents (100 computers, 3000 tons of wheat), label it F. Would it be possible for the economy to produce this combination of the two goods?Why or why not? B.Next, find the point that represents (300

15、 computers, 3500 tons of wheat), label it G. Would it be possible for the economy to produce this combination of the two goods?1617Point F:100 computers, 3000 tons wheatPoint F requires 40,000 hours of labor. Possible but not efficient: could get more of either good w/o sacrificing any of the other.

16、F18Point G:300 computers, 3500 tons wheatPoint G requires 65,000 hours of labor. Not possible because economy only has 50,000 hours.GTHINKING LIKE AN ECONOMIST19The PPF: What We Know So FarPoints on the PPF (like A E)possibleefficient: all resources are fully utilized (資源充分利用)Points under the PPF (l

17、ike F) possiblenot efficient: some resources underutilized (e.g., workers unemployed, factories idle （工廠空閑）) Points above the PPF (like G) not possibleTHINKING LIKE AN ECONOMIST20The PPF and Opportunity CostRecall: The opportunity cost of an item is what must be given up to obtain that item. Moving

18、along a PPF involves shifting resources (e.g., labor) from the production of one good to the other. Society faces a tradeoff: Getting more of one good requires sacrificing some of the other. The slope（斜率）（斜率） of the PPF tells you the opportunity cost of one good in terms of the other. （斜率可以作為機(jī)會(huì)成本的度量

19、指標(biāo)）THINKING LIKE AN ECONOMIST21The PPF and Opportunity CostThe slope of a line equals the “rise over the run,” the amount the line rises when you move to the right by one unit.1000100slope = 10Here, the opportunity cost of a computer is 10 tons of wheat.22In which country is the opportunity cost of

20、cloth lower?FRANCEENGLAND23FRANCEENGLANDEngland, because its PPF is not as steep as Frances.THINKING LIKE AN ECONOMIST24Economic Growth （經(jīng)濟(jì)增長經(jīng)濟(jì)增長） and the PPFWith additional resources or an improvement in technology（資源增加或者技術(shù)提升）, the economy can produce more computers,more wheat, or any combination i

21、n between. Economic growth shifts the PPF outward.25The Shape of the PPFThe PPF could be a straight line, or bow-shaped （弓形）Depends on what happens to opportunity cost as economy shifts resources from one industry to the other.If opp. cost（機(jī)會(huì)成本） remains constant, PPF is a straight line. （機(jī)會(huì)成本是常數(shù)，PPF

22、為直線）(In the previous example, opp. cost of a computer was always 10 tons of wheat.)If opp. cost of a good rises as the economy produces more of the good, PPF is bow-shaped.（通常情況：機(jī)會(huì)成本遞增導(dǎo)致PPF為弓形） THINKING LIKE AN ECONOMIST26Mountain BikesBeerAs the economy shifts resources from beer to mountain bikes:

23、PPF becomes steeperopp. cost of mountain bikes increases Why the PPF Might Be Bow-Shaped 生產(chǎn)可能性邊界為何有時(shí)候是弓形的生產(chǎn)可能性邊界為何有時(shí)候是弓形的THINKING LIKE AN ECONOMIST27AAt point A, most workers are producing beer, even those that are better suited to building bikes.（太多的資源生產(chǎn)啤酒，生產(chǎn)效率低下）So, do not have to give up much bee

24、r to get more bikes.Mountain BikesBeerAt A, opp. cost of mtn bikes is low.Why the PPF Might Be Bow-Shaped 生產(chǎn)可能性邊界為何有時(shí)候是弓形的生產(chǎn)可能性邊界為何有時(shí)候是弓形的THINKING LIKE AN ECONOMIST28BAt B, most workers are producing bikes. The few left in beer are the best brewers.（最好的啤酒制造者）Producing more bikes would require shifti

25、ng some of the best brewers away from beer production, would cause a big drop in beer output. Mountain BikesBeerAt B, opp. cost of mtn bikes is high.Why the PPF Might Be Bow-Shaped 生產(chǎn)可能性邊界為何有時(shí)候是弓形的生產(chǎn)可能性邊界為何有時(shí)候是弓形的隨著生產(chǎn)登山車的勞動(dòng)投入增加，大量高效率生產(chǎn)啤酒的工人不能再生產(chǎn)啤酒，轉(zhuǎn)而生產(chǎn)登山車，從而機(jī)會(huì)成本逐漸增加。THINKING LIKE AN ECONOMIST29So, P

26、PF is bow-shaped when different workers have different skills, different opportunity costs of producing one good in terms of the other.（不同工人生產(chǎn)技能不同）The PPF would also be bow-shaped when there is some other resource, or mix of resources with varying opportunity costs（未考慮的其他資源導(dǎo)致的機(jī)會(huì)成本存在差異）(E.g., differe

27、nt types of land suited for different uses). (土地資源opp.cost是不同的)Why the PPF Might Be Bow-Shaped 生產(chǎn)可能性邊界為何有時(shí)候是弓形的生產(chǎn)可能性邊界為何有時(shí)候是弓形的THINKING LIKE AN ECONOMIST30The PPF: A SummaryThe PPF shows all combinations of two goods that an economy can possibly produce, given its resources and technology. （給定技術(shù)、資源，

28、最大化生產(chǎn)兩種產(chǎn)品的全部可能組合）The PPF illustrates the concepts of tradeoff （權(quán)衡取舍）（權(quán)衡取舍）and opportunity cost（機(jī)會(huì)成機(jī)會(huì)成本）本）, efficiency （效率）（效率）and inefficiency （非效（非效率）率）, unemployment（失業(yè)）（失業(yè)）, and economic growth（經(jīng)濟(jì)增長）（經(jīng)濟(jì)增長）. A bow-shaped PPF illustrates the concept of increasing opportunity cost. （遞增的機(jī)會(huì)成本）（遞增的機(jī)會(huì)成本

29、） THINKING LIKE AN ECONOMIST31Microeconomics and Macroeconomics微觀經(jīng)濟(jì)學(xué)微觀經(jīng)濟(jì)學(xué) 和和 宏觀經(jīng)濟(jì)學(xué)宏觀經(jīng)濟(jì)學(xué)Microeconomics is the study of how households and firms make decisions and how they interact in markets. （微觀經(jīng)濟(jì)學(xué)研究家庭和企業(yè)如何做決策，微觀經(jīng)濟(jì)學(xué)研究家庭和企業(yè)如何做決策，以及他們?cè)谑袌?chǎng)中如何相互作用以及他們?cè)谑袌?chǎng)中如何相互作用）Macroeconomics is the study of economy-wid

30、e phenomena, including inflation, unemployment, and economic growth. （宏觀經(jīng)濟(jì)學(xué)研究經(jīng)濟(jì)總體現(xiàn)象，宏觀經(jīng)濟(jì)學(xué)研究經(jīng)濟(jì)總體現(xiàn)象，包括通脹、失業(yè)、經(jīng)濟(jì)增長問題等等包括通脹、失業(yè)、經(jīng)濟(jì)增長問題等等）These two branches of economics are closely intertwined （緊密聯(lián)系）（緊密聯(lián)系）, yet distinct （有區(qū)別）（有區(qū)別） they address different questions. The Economist as Policy Advisor作為政策顧問的經(jīng)濟(jì)學(xué)

31、家作為政策顧問的經(jīng)濟(jì)學(xué)家As scientists, economists make positive statements（實(shí)證表（實(shí)證表述）述）, which attempt to describe the world as it is. 實(shí)證表述指的是解釋解釋經(jīng)濟(jì)現(xiàn)象，這是經(jīng)濟(jì)學(xué)家作為科學(xué)家的一種角色As policy advisors, economists make normative statements, 規(guī)范表述規(guī)范表述which attempt to prescribe how the world should be. 規(guī)范表述試圖描述世界應(yīng)該應(yīng)該是什么樣的觀點(diǎn)。Positi

32、ve statements can be confirmed or refuted, normative statements cannot. （實(shí)證表述可以被證實(shí)或否定，規(guī)范表述則不能）Govt employs many economists for policy advice. E.g., the U.S. President has a Council of Economic Advisors, which the author of this textbook chaired from 2003 to 2005. 3233Which of these statements are “p

33、ositive” (實(shí)證) and which are “normative” （規(guī)范）? How can you tell the difference?a.Prices rise when the government increases the quantity of money. （政府增加貨幣數(shù)量，價(jià)格會(huì)上漲）b. The government should print less money. （政府應(yīng)該少發(fā)貨幣）c. A tax cut （減稅）is needed to stimulate the economy （刺激經(jīng)濟(jì)）. d.An increase in the price

34、 of burritos （卷餅） will cause an increase in consumer demand for video rentals （錄像租賃）.34a. Prices rise when the government increases the quantity of money. Positive describes a relationship, could use data to confirm or refute.b. The government should print less money. Normative this is a value judgm

35、ent, cannot be confirmed or refuted.35c. A tax cut is needed to stimulate the economy. Normative another value judgment.d. An increase in the price of burritos will cause an increase in consumer demand for video rentals.Positive describes a relationship. Note that a statement need not be true to be

36、positive.Why Economists Disagree為什么經(jīng)濟(jì)學(xué)家意見分歧為什么經(jīng)濟(jì)學(xué)家意見分歧pThey may disagree on theories about how the world works.（實(shí)證表述不一樣） 對(duì)關(guān)于世界如何運(yùn)行的理論看法不同。pThey may hold different values and, thus, different normative views. （規(guī)范表述不一樣） 他們可能有不同的價(jià)值觀，從而有不同的規(guī)范性觀點(diǎn)。THINKING LIKE AN ECONOMIST37Propositions about Which Most

37、Economists Agree (and % who agree)continued1. 租金上限減少了可得到的住房數(shù)量和質(zhì)量。（93）2. 關(guān)稅和進(jìn)口配額通常降低了普遍的經(jīng)濟(jì)福利。（93）3. 有伸縮性和浮動(dòng)性的匯率提供了一種有效的國際貨幣協(xié)定。（90）4. 財(cái)政政策 例如，減稅和（或）增加政府支出 對(duì)低于充分就業(yè)的經(jīng)濟(jì)有重要的刺激效應(yīng)。（90）5. 如果要平衡聯(lián)邦預(yù)算，應(yīng)該在經(jīng)濟(jì)周期中而不是每年中來實(shí)現(xiàn)。（85）THINKING LIKE AN ECONOMIST38Propositions about Which Most Economists Agree (and % agreeing)6. 現(xiàn)金轉(zhuǎn)移支付